1. Field of the Invention
This invention relates to a method for stripping or eluting material from loaded solid particles. Typically, the loaded particles to which the stripping method is applied will be the loaded particles obtained as the output product from an absorber process wherein a fluid to be treated is contacted with solid particles, and the particles take up and become loaded with material initially present in the fluid. The invention provides a method whereby the material can be efficiently stripped from the particles.
An example of a fluid/solid particle contacting process, in conjunction with which the method of the present method may be employed, is described in U.S. patent application Ser. No. 399,515, filed Sept. 21, 1973 and now abandoned in favor of continuation-in-part application Ser. No. 576,872, filed May 12, 1975 to which reference should be made for further details.
2. Description of the Prior Art
Prior proposals of techniques for stripping material from solid particles of which the applicant is aware have suffered to a greater or lesser degree from disadvantages which detract from the efficiency of the stripping method.
As examples of prior stripping methods, there may be mentioned the methods described in Kingsbury U.S. Pat. No. 3,627,705, Arden U.S. Pat. No. 3,674,685 and the method described in applicant's above mentioned U.S. patent application. These describe stripping methods in which loaded resin particles are introduced into the bottom of a regeneration column and travel upwardly through the column. Eluant liquid is passed downwardly through the column counter-currently to the movement of the resin particles, and eluate, i.e., eluant containing the material eluted from the particles, is discharged from the lower region of the column. The applicant has observed that in these prior-described methods, variable quantities of liquid enter the regeneration column together with the input of the resin particles to the column, and that therefore the concentrations of the reactants in the column are unpredictable, so that the optimum concentrations for efficient stripping cannot readily be maintained. Further, in instances where the eluate comprises valuable metal ions or other valuable products, the eluate inevitably becomes diluted, so that recovery of the valuable material is made more difficult and more costly.